Laser devices are known from the prior art in various embodiments and have, for example, semiconductor laser elements in the form of laser diode bars or stacks of laser diode bars, which are also often referred to as “stacks.” In laser devices of the aforementioned type the light, which is emitted by the individual laser diode bars or, more specifically, the stacks of laser diode bars and which is linearly polarized in different ways, can be combined with the aid of a polarization coupler to form a resulting laser beam and then can be focused with suitable optics, for example, directly on a workpiece to be machined or can be introduced into a light conducting fiber.
During the polarization coupling process, at least two different linearly polarized, in particular, mutually perpendicularly polarized, laser beams, which propagate in two different, in particular, mutually orthogonal, spatial directions, are coupled with the aid of a polarization coupler and, as a result, are overlaid collinearly to form a resulting laser beam. Such polarization couplers are often designed as mirrors having a dielectric coating, which has ideally, for example, a degree of reflection Rs=100% for a direction of polarization that is perpendicular to the plane of incidence and has ideally a degree of reflection Rp=0% for a direction of polarization that is parallel to the plane of incidence.